Improvement in recording-points for chemical telegraphs



UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, NEWARK, NEW JERSEY, ASSIGNOR TO HIMSELF AND GEORGE HARRINGTON, OF WASHINGTON, DISTRICT OF COLUMBIA.

IMPROVEMENT IN RECORDING-POINTS FOR CHEMICAL TELEGRAPHS.

Specification forming part of Letters Patent No. 168,467., dated October 5, 1875; application filed January 26, 1875.

CASE 105.

is of extreme delicacy, the marks being due probably to the finely-divided oxide of ruthinium formed by the electrolytic oxygen.

I claim Areoording-point formed of metallic ruthinium in a chemical telegraph, substantially as set forth.

Signed by me this 18th day of January, A. D. 1875.

THOS. A. EDISON.

Witnesses:

GEO. T. PINOKNEY, CHAS. H. SMITH. 

